At 5:57 on a Friday afternoon a major incident took place on the A12: six cars were involved in a tragic collision that left two dead at the scene two other critically wounded and the surviving victims forever changed-their lives forever entwined. When the father of one of the victims files a suit against the police department for alleged complicity in the accident Detective Inspector John Tolin (Douglas Henshall) just back from an extended leave must come to terms with his own past-and with his partner in the investigation Senior Investigating Officer Ann Stallwood (Kate Ash field)-if he has any hope of untangling the carnage and understanding what caused the accident that threw so many lives together for better or for worse. By focusing on the how the individuals involved in the crash spent their days leading up to the crash Tolin and Stallwood uncover much more than just the cause of the accident. Together they must somehow find a way to continue their investigation once the suit against the Met is dropped if they are to have any hope of solving crimes from smuggling to murder-even genocide.